By all appearances, Brooke Greenberg is an average baby. She giggles and coos when she's happy and enjoys rocking in her swing. She can also be quite stubborn and is quick to voice loud disapproval when she's unhappy with something. At about sixteen pounds and 30 inches tall, the curly haired little girl appears to be a typical six-month-old. But Brooke Greenberg isn't an infant, she's sixteen years old and something of medical mystery.

Since her birth, Brooke's body and brain have not aged in the conventional sense. She remains the size of an infant and has the mental capacity of a toddler. Her bone age is estimated to be about 10 years old and she has a mouth full of baby teeth. She rides in a stroller and, because her esophagus is so small, must be fed through a tube.

"There've been very minimal changes in Brooke's brain," says Dr. Richard Walker of the University of South Florida College of Medicine. "Various parts of her body, rather than all being at the same stage, seem to be disconnected."
Experts have been unable to diagnose Brooke with any known genetic syndrome and have yet to discover a chromosomal abnormality that would explain her condition.

But for all the mystery that surrounds Brooke, there are also a few miracles. She has survived several serious health crises in her young life, including a near-fatal brain tumor that suddenly and without explanation disappeared on its own.

Scientists believe that somewhere in Brooke's genetic makeup may lie the answer to the eternal question of why we age and, perhaps, how to slow that process. "Without being sensational, I'd say this is an opportunity for us to answer the question, why we're mortal, or at least to test it," Walker says. "And if we're wrong, we can discard it. But if we're right, we've got the golden ring."

"Brooke is the nucleus of our family," says her father, Howard Greenberg. What if Brooke holds the secret to aging? "We'd like to find out. We'd like to help people. Everybody's here for a reason. Maybe this is why Brooke is here."